1. Field of the Invention
The present invention relates to a tie-down anchor which is a fitting used to provide a point of attachment for a strap, belt, rope, chain, cable, or other device, and which can be positioned at a selected location along a fixed track.
Tie-down anchors of the type disclosed herein find advantageous use in connection with cargo handling equipment for securing the cargo to a track mounted on a pallet or on a fixed structural portion of an aircraft, ship, train, truck, or other transport vehicle.
2. The Prior Art
A well known technique in the art is to mount a track to a pallet on which cargo is to be secured or to a structural member of a vehicle on which cargo is to be transported, to provide a plurality of positions at which fittings can be attached to the track to permit straps, cables, etc. to be connected to the track to hold the cargo in its intended place. A particular type of track, as shown in U.S. Pat. No. 4,020,770 of May 3, 1977 has become more or less standard throughout the industry.
The present invention is well suited for use with this type of track, but definitely is not limited to use with such track.
A variety of tie-down anchors is known in the prior art and that shown in U.S. Pat. No. 4,020,770 is typical of a family of anchors known in the prior art. The anchors in this family all include more than two parts having specialized shapes and requiring careful assembly. As will be seen below, the anchor of the present invention is far simpler in its structure than any of the members of this family and can easily be distinguished from anchors of this family. There are a number of U.S. patents which describe anchors of the family of anchors describe.
An altogether different, and more pertinent, family of fasteners is that, often referred to as "butterfly fasteners"; all consist of a pair of identical parts which are inserted back-to-back into a track. One such anchor is that manufactured by Aeroquip Corporation of Jackson, Mich. That anchor is designed for use with a type of track which is used in the trucking industry, but the anchor will not fit into the standard cargo track previously referred to.
Each half of the Aeroquip fitting includes a foot which extends perpendicular to the portions of the fitting through which the belt passes. The soles of the feet are positioned toward each other and the feet are then extended through one of the holes in the track. Thereafter, the belt-receiving portions are brought together, causing the feet to pivot away from each other.
Another, and more pertinent, member of this second family of anchors is shown in FIGS. 8 and 9. This fitting described in U.S. Pat. No. 3,422,508 issued Jan. 21, 1969 to Higuchi. This fitting also consists of two identical parts positioned back-to-back. Unlike the Aeroquip fitting, Higuchi's fitting, is intended for use with a cargo track of the type previously describe.
Higuchi's contemplates that his fitting is to be made of a single formed plate of metal. Such a design is unacceptable to the industry because the width of the opening in the track between the extending projections is greater than twice the thickness of the opening receiving the foot of the stud. As shown in the Higuchi patent, and the back portions 16, 17 of his plates, which extend perpendicularly out of the track, do not serve--after insertion--to keep the halves positioned in the track, because they are too thin, being of the same thickness as the foot portion, and the halves fall out of the track in use. Higuchi provides devices such as a looped strap, hinged clip, and insertable pin to hold the plates together so they will not fall out. Such structures require extra steps to apply, are susceptible to damage, and may become lost if not attached.
These auxiliary structures are dispensed with in the present invention, in which the back portion is thicker than the foot portion so that when the two halves are inserted back-to-back in the track, the space between the straight portions of the slot of the track is largely filled by the back portions of the halves, so that in a preferred embodiment, lateral movement of the anchor within the track is limited by contact of the back portions with the straight portions of the edge of the flange of the track.